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// Copyright 2018-2020 Parity Technologies (UK) Ltd. // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. extern crate proc_macro; mod contract; mod ink_test; mod trait_def; use proc_macro::TokenStream; /// Entry point for writing ink! smart contracts. /// /// If you are a beginner trying to learn ink! we recommend you to check out /// our extensive [ink! workshop](https://substrate.dev/substrate-contracts-workshop/#/). /// /// **Note:** In all below examples we will be using `ink_lang` crate aliased as just `ink`. /// You can do this yourself by adding the following line to your code: /// `use ink_lang as ink;` /// /// # Description /// /// The macro does analysis on the provided smart contract code and generates /// proper code. /// /// ink! smart contracts can compile in several different modes. /// There are two main compilation models using either /// - on-chain mode: `no_std` + WebAssembly as target /// - off-chain mode: `std` /// /// We generally use the on-chain mode for actual smart contract deployment /// whereas we use the off-chain mode for smart contract testing using the /// off-chain environment provided by the `ink_env` crate. /// /// # Usage /// /// ## Header Arguments /// /// The `#[ink::contract]` macro can be provided with some additional comma-separated /// header arguments: /// /// - `dynamic_storage_allocator: bool` /// /// Tells the ink! code generator to allow usage of ink!'s built-in dynamic /// storage allocator. /// - `true`: Use the dynamic storage allocator provided by ink!. /// - `false`: Do NOT use the dynamic storage allocator provided by ink!. /// /// This feature is generally only needed for smart contracts that try to model /// their data in a way that contains storage entites within other storage /// entities. /// /// Contract writers should try to write smart contracts that do not depend on the /// dynamic storage allocator since enabling it comes at a cost of increased Wasm /// file size. Although it will enable interesting use cases. Use it with care! /// /// An example for this is the following type that could potentially be used /// within a contract's storage struct definition: /// ``` /// // A storage vector of storage vectors. /// # use ink_storage as storage; /// # type _unused = /// storage::Vec<storage::Vec<i32>> /// # ; /// ``` /// /// **Usage Example:** /// ``` /// # use ink_lang as ink; /// #[ink::contract(dynamic_storage_allocator = true)] /// mod my_contract { /// # #[ink(storage)] /// # pub struct MyStorage; /// # impl MyStorage { /// # #[ink(constructor)] /// # pub fn construct() -> Self { MyStorage {} } /// # #[ink(message)] /// # pub fn message(&self) {} /// # } /// // ... /// } /// ``` /// /// **Default value:** `false` /// /// - `compile_as_dependency: bool` /// /// Tells the ink! code generator to **always** or **never** /// compile the smart contract as if it was used as a dependency of another ink! /// smart contract. /// /// Normally this flag is only really useful for ink! developers who /// want to inspect code generation of ink! smart contracts. /// The author is not aware of any particular practical use case for users that /// makes use of this flag but contract writers are encouraged to disprove this. /// /// Note that it is recommended to make use of the built-in crate feature /// `ink-as-dependency` to flag smart contract dependencies listed in a contract's /// `Cargo.toml` as actual dependencies to ink!. /// /// **Usage Example:** /// ``` /// # use ink_lang as ink; /// #[ink::contract(compile_as_dependency = true)] /// mod my_contract { /// # #[ink(storage)] /// # pub struct MyStorage; /// # impl MyStorage { /// # #[ink(constructor)] /// # pub fn construct() -> Self { MyStorage {} } /// # #[ink(message)] /// # pub fn message(&self) {} /// # } /// // ... /// } /// ``` /// /// **Default value:** Depends on the crate feature propagation of `Cargo.toml`. /// /// - `env: impl Environment` /// /// Tells the ink! code generator which environment to use for the ink! smart contract. /// The environment must implement the `Environment` (defined in `ink_env`) trait and provides /// all the necessary fundamental type definitions for `Balance`, `AccountId` etc. /// /// When using a custom `Environment` implementation for a smart contract all types /// that it exposes to the ink! smart contract and the mirrored types used in the runtime /// must be aligned with respect to SCALE encoding and semantics. /// /// **Usage Example:** /// /// Given a custom `Environment` implementation: /// ``` /// pub struct MyEnvironment; /// /// impl ink_env::Environment for MyEnvironment { /// const MAX_EVENT_TOPICS: usize = 3; /// type AccountId = u64; /// type Balance = u128; /// type Hash = [u8; 32]; /// type Timestamp = u64; /// type BlockNumber = u32; /// } /// ``` /// A user might implement their ink! smart contract using the above custom `Environment` /// implementation as demonstrated below: /// ``` /// # use ink_lang as ink; /// #[ink::contract(env_types = MyEnvironment)] /// mod my_contract { /// # pub struct MyEnvironment; /// # /// # impl ink_env::Environment for MyEnvironment { /// # const MAX_EVENT_TOPICS: usize = 3; /// # type AccountId = u64; /// # type Balance = u128; /// # type Hash = [u8; 32]; /// # type Timestamp = u64; /// # type BlockNumber = u32; /// # } /// # /// # #[ink(storage)] /// # pub struct MyStorage; /// # impl MyStorage { /// # #[ink(constructor)] /// # pub fn construct() -> Self { MyStorage {} } /// # #[ink(message)] /// # pub fn message(&self) {} /// # } /// // ... /// } /// ``` /// /// **Default value:** `DefaultEnvironment` defined in `ink_env` crate. /// /// ## Anaylsis /// /// The `#[ink::contract]` macro fully analyses its input smart contract /// against invalid arguments and structure. /// /// Some example rules include but are not limited to: /// /// - There must be exactly one `#[ink(storage)]` struct. /// /// This struct defines the layout of the storage that the ink! smart contract operates on. /// The user is able to use a variety of built-in facilities, combine them in various ways /// or even provide their own implementations of storage data structures. /// /// For more information visit the `ink_storage` crate documentation. /// /// **Example:** /// /// ``` /// # use ink_lang as ink; /// #[ink::contract] /// mod flipper { /// #[ink(storage)] /// pub struct Flipper { /// value: bool, /// } /// # impl Flipper { /// # #[ink(constructor)] /// # pub fn construct() -> Self { Flipper { value: false } } /// # #[ink(message)] /// # pub fn message(&self) {} /// # } /// } /// ``` /// /// - There must be at least one `#[ink(constructor)]` defined method. /// /// Methods flagged with `#[ink(constructor)]` are special in that they are dispatchable /// upon contract instantiation. A contract may define multiple such constructors which /// allow users of the contract to instantiate a contract in multiple different ways. /// /// **Example:** /// /// Given the `Flipper` contract definition above we add an `#[ink(constructor)]` /// as follows: /// /// ``` /// # use ink_lang as ink; /// # #[ink::contract] /// # mod flipper { /// # #[ink(storage)] /// # pub struct Flipper { /// # value: bool, /// # } /// impl Flipper { /// #[ink(constructor)] /// pub fn new(initial_value: bool) -> Self { /// Flipper { value: false } /// } /// # #[ink(message)] /// # pub fn message(&self) {} /// } /// # } /// ``` /// /// - There must be at least one `#[ink(message)]` defined method. /// /// Methods flagged with `#[ink(message)]` are special in that they are dispatchable /// upon contract invocation. The set of ink! messages defined for an ink! smart contract /// define its API surface with which users are allowed to interact. /// /// An ink! smart contract can have multiple such ink! messages defined. /// /// **Note:** /// /// - An ink! message with a `&self` receiver may only read state whereas an ink! message /// with a `&mut self` receiver may mutate the contract's storage. /// /// **Example:** /// /// Given the `Flipper` contract definition above we add some `#[ink(message)]` definitions /// as follows: /// /// ``` /// # use ink_lang as ink; /// # #[ink::contract] /// # mod flipper { /// # #[ink(storage)] /// # pub struct Flipper { /// # value: bool, /// # } /// impl Flipper { /// # #[ink(constructor)] /// # pub fn new(initial_value: bool) -> Self { /// # Flipper { value: false } /// # } /// /// Flips the current value. /// #[ink(message)] /// pub fn flip(&mut self) { /// self.value = !self.value; /// } /// /// /// Returns the current value. /// #[ink(message)] /// pub fn get(&self) -> bool { /// self.value /// } /// } /// # } /// ``` /// /// **Payable Messages:** /// /// An ink! message by default will reject calls that additional fund the smart contract. /// Authors of ink! smart contracts can make an ink! message payable by adding the `payable` /// flag to it. An example below: /// /// Note that ink! constructors are always implicitly payable and thus cannot be flagged /// as such. /// /// ``` /// # use ink_lang as ink; /// # #[ink::contract] /// # mod flipper { /// # #[ink(storage)] /// # pub struct Flipper { /// # value: bool, /// # } /// impl Flipper { /// # #[ink(constructor)] /// # pub fn new(initial_value: bool) -> Self { /// # Flipper { value: false } /// # } /// /// Flips the current value. /// #[ink(message)] /// #[ink(payable)] // You can either specify payable out-of-line. /// pub fn flip(&mut self) { /// self.value = !self.value; /// } /// /// /// Returns the current value. /// #[ink(message, payable)] // ... or specify payable inline. /// pub fn get(&self) -> bool { /// self.value /// } /// } /// # } /// ``` /// /// **Controlling the messages selector:** /// /// Every ink! message and ink! constructor has a unique selector with which the /// message or constructor can be uniquely identified within the ink! smart contract. /// These selectors are mainly used to drive the contract's dispatch upon calling it. /// /// An ink! smart contract author can control the selector of an ink! message or ink! /// constructor using the `selector` flag. An example is shown below: /// /// ``` /// # use ink_lang as ink; /// # #[ink::contract] /// # mod flipper { /// # #[ink(storage)] /// # pub struct Flipper { /// # value: bool, /// # } /// impl Flipper { /// #[ink(constructor)] /// #[ink(selector = "0xDEADBEEF")] // Works on constructors as well. /// pub fn new(initial_value: bool) -> Self { /// Flipper { value: false } /// } /// /// # /// Flips the current value. /// # #[ink(message)] /// # #[ink(selector = "0xCAFEBABE")] // You can either specify selector out-of-line. /// # pub fn flip(&mut self) { /// # self.value = !self.value; /// # } /// # /// /// Returns the current value. /// #[ink(message, selector = "0xFEEDBEEF")] // ... or specify selector inline. /// pub fn get(&self) -> bool { /// self.value /// } /// } /// # } /// ``` /// /// ## Interacting with the Contract Executor /// /// The `ink_env` crate provides facitilies to interact with the contract executor that /// connects ink! smart contracts with the outer world. /// /// For example it is possible to query the current call's caller via: /// ``` /// # ink_env::test::run_test::<ink_env::DefaultEnvironment, _>(|_| { /// let caller = ink_env::caller::<ink_env::DefaultEnvironment>(); /// # let _caller = caller; /// # Ok(()) /// # }).unwrap(); /// ``` /// /// However, ink! provides a much simpler way to interact with the contract executor /// via its environment accessor. An example below: /// /// ``` /// # use ink_lang as ink; /// # /// #[ink::contract] /// mod greeter { /// #[ink(storage)] /// pub struct Greeter; /// /// impl Greeter { /// #[ink(constructor)] /// pub fn new() -> Self { /// let caller = Self::env().caller(); /// let message = format!("thanks for instantiation {:?}", caller); /// ink_env::debug_println(&message); /// Greeter {} /// } /// /// #[ink(message, payable)] /// pub fn fund(&mut self) { /// let caller = self.env().caller(); /// let value = self.env().transferred_balance(); /// let message = format!("thanks for the funding of {:?} from {:?}", value, caller); /// ink_env::debug_println(&message); /// } /// } /// } /// ``` /// /// ## Events /// /// An ink! smart contract may define events that it can emit during contract execution. /// Emitting events can be used by third party tools to query information about a contract's /// execution and state. /// /// The following example ink! contract shows how an event `Transferred` is defined and /// emitted in the `#[ink(constructor)]`. /// /// ``` /// # use ink_lang as ink; /// # /// #[ink::contract] /// mod erc20 { /// /// Defines an event that is emitted every time value is transferred. /// #[ink(event)] /// pub struct Transferred { /// from: Option<AccountId>, /// to: Option<AccountId>, /// value: Balance, /// } /// /// #[ink(storage)] /// pub struct Erc20 { /// total_supply: Balance, /// // more fields ... /// } /// /// impl Erc20 { /// #[ink(constructor)] /// pub fn new(initial_supply: Balance) -> Self { /// let caller = Self::env().caller(); /// Self::env().emit_event(Transferred { /// from: None, /// to: Some(caller), /// value: initial_supply, /// }); /// Self { total_supply: initial_supply } /// } /// /// #[ink(message)] /// pub fn total_supply(&self) -> Balance { /// self.total_supply /// } /// } /// } /// ``` /// /// ## Example: Flipper /// /// The below code shows the complete implementation of the so-called Flipper /// ink! smart contract. /// For us it acts as the "Hello, World!" of the ink! smart contracts because /// it is minimal while still providing some more or less useful functionality. /// /// It controls a single `bool` value that can be either `false` or `true` /// and allows the user to flip this value using the `Flipper::flip` message /// or retrieve the current value using `Flipper::get`. /// /// ``` /// use ink_lang as ink; /// /// #[ink::contract] /// pub mod flipper { /// #[ink(storage)] /// pub struct Flipper { /// value: bool, /// } /// /// impl Flipper { /// /// Creates a new flipper smart contract initialized with the given value. /// #[ink(constructor)] /// pub fn new(init_value: bool) -> Self { /// Self { value: init_value } /// } /// /// /// Flips the current value of the Flipper's bool. /// #[ink(message)] /// pub fn flip(&mut self) { /// self.value = !self.value; /// } /// /// /// Returns the current value of the Flipper's bool. /// #[ink(message)] /// pub fn get(&self) -> bool { /// self.value /// } /// } /// } /// ``` #[proc_macro_attribute] pub fn contract(attr: TokenStream, item: TokenStream) -> TokenStream { contract::generate(attr.into(), item.into()).into() } /// Marks trait definitions to ink! as special ink! trait definitions. /// /// There are some restrictions that apply to ink! trait definitions that /// this macro checks. Also ink! trait definitions are required to have specialized /// structure so that the main [`#[ink::contract]`](`macro@crate::contract`) macro can /// properly generate code for its implementations. /// /// # Example: Definition /// /// ``` /// use ink_lang as ink; /// # type Balance = <ink_env::DefaultEnvironment as ink_env::Environment>::Balance; /// /// #[ink::trait_definition] /// pub trait Erc20 { /// /// Constructs a new ERC-20 compliant smart contract using the initial supply. /// #[ink(constructor)] /// fn new(initial_supply: Balance) -> Self; /// /// /// Returns the total supply of the ERC-20 smart contract. /// #[ink(message)] /// fn total_supply(&self) -> Balance; /// /// // etc. /// } /// ``` /// /// # Example: Implementation /// /// Given the above trait definition you can implement it as shown below: /// /// ``` /// # use ink_lang as ink; /// # /// #[ink::contract] /// mod base_erc20 { /// # // We somehow cannot put the trait in the doc-test crate root due to bugs. /// # #[ink_lang::trait_definition] /// # pub trait Erc20 { /// # /// Constructors a new ERC-20 compliant smart contract using the initial supply. /// # #[ink(constructor)] /// # fn new(initial_supply: Balance) -> Self; /// # /// # /// Returns the total supply of the ERC-20 smart contract. /// # #[ink(message)] /// # fn total_supply(&self) -> Balance; /// # } /// # /// #[ink(storage)] /// pub struct BaseErc20 { /// total_supply: Balance, /// // etc .. /// } /// /// impl Erc20 for BaseErc20 { /// #[ink(constructor)] /// fn new(initial_supply: Balance) -> Self { /// Self { total_supply: initial_supply } /// } /// /// /// Returns the total supply of the ERC-20 smart contract. /// #[ink(message)] /// fn total_supply(&self) -> Balance { /// self.total_supply /// } /// /// // etc .. /// } /// } /// ``` #[proc_macro_attribute] pub fn trait_definition(attr: TokenStream, item: TokenStream) -> TokenStream { trait_def::analyze(attr.into(), item.into()).into() } /// Defines a unit test that makes use of ink!'s off-chain testing capabilities. /// /// If your unit test does not require the existence of an off-chain environment /// it is fine to not use this macro since it bears some overhead with the test. /// /// Note that this macro is not required to run unit tests that require ink!'s /// off-chain testing capabilities but merely improves code readability. /// /// ## How do you find out if your test requires the off-chain environment? /// /// Normally if the test recursively uses or invokes some contract methods that /// call a method defined in `self.env()` or `Self::env()`. /// /// An examples is the following: /// /// ```no_compile /// let caller: AccountId = self.env().caller(); /// ``` /// /// # Example /// /// ``` /// use ink_lang as ink; /// /// #[cfg(test)] /// mod tests { /// // Conventional unit test that works with assertions. /// #[ink::test] /// fn test1() { /// // test code comes here as usual /// } /// /// // Conventional unit test that returns some Result. /// // The test code can make use of operator-`?`. /// #[ink::test] /// fn test2() -> Result<(), ink_env::Error> { /// // test code that returns a Rust Result type /// } /// } /// ``` #[proc_macro_attribute] pub fn test(attr: TokenStream, item: TokenStream) -> TokenStream { ink_test::generate(attr.into(), item.into()).into() } #[cfg(test)] pub use contract::generate_or_err;